Silicon carbide is expected as a material for next generation semiconductor devices. Silicon carbide has superior physical properties such as a band gap of about 3 times, a breakdown field strength of about 10 times, and a thermal conductivity of about 3 times of silicon. By utilizing the physical properties, a semiconductor device with low loss and high temperature operation can be achieved.
As a structure for reducing on-resistance of a metal oxide semiconductor field effect transistor (MOSFET) using silicon carbide, there is a trench gate type MOSFET in which a gate electrode is provided in a trench. In the trench gate type MOSFET, the on-resistance is reduced by increasing a channel density per unit area. Further reduction of the on-resistance in the trench gate type MOSFET is expected.